1. Field of the Invention
The present invention relates to mechanically propelled metered dispensers which are plunger-activated by a cocking mechanism and dispense a liquid stream or a mist of liquid dispensing material, e.g., medication. The present invention dispensers include provision for automatic advancement of a liquid in a metered amount into the dispensing chamber in response to pulling the cocking mechanism to the cocked (loaded) position.
2. Information Disclosure Statement
The following patents are representative of metered, mechanically propelled, liquid dispensers:
U.S. Pat. No. 3,934,585 to David M. Maurice discloses a method and apparatus for applying therapeutic eye drops to the eye by metering a predetermined volume of fluid and rapidly applying a pressure to one end of the metered fluid for forcing the fluid from a nozzle of means defining a small passageway such as and open-ended tube as a droplet having sufficient velocity to travel a generally horizontal distance in space to the eye. Unit dose application and multiple dose applications are included and provision is made for preventing anticipatory blinking of the eye during self-administration.
U.S. Pat. No. 5,267,986 describes and illustrates a cartridge for actuating a piston-like or accordion-like dispenser-vial for applying medication to any eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to actuate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a trigger mechanism for releasing the cylinder from the locked position so that a drop is released from the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul de sac.
U.S. Pat. No. 5,401,259 discloses a cartridge for actuating a piston-like or accordion-like dispenser-vial for applying medicament to the eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to activate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a lever mechanism for releasing the cylinder form the locked position so that a drop is released from the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul-de-sac.
U.S. Pat. No. 5,613,957 to Daniel Py discloses an apparatus used for applying medicament to an eye and to store the medicament in a medicament chamber. A nozzle is coupled in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an nozzle portion. A tight interface is defined between the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The interface opens in response to the flow of medicament of sufficient pressure into it to permit the passage of medicament through the nozzle for release into the eye.
U.S. Pat. No. 5,685,869 to Daniel Py describes and illustrates an apparatus used to apply medicament to an eye and to store the medicament in the medicament chamber. A nozzle is coupled in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an inner nozzle portion received within the outer nozzle portion. A seam is formed by the interface of the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The seam opens in response to the flow of medicament or sufficient pressure into the seam to permit the passage of medicament through the nozzle for release into the eye.
Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.
The present invention is directed to a mechanically propelled, liquid metered dispenser for dispensing liquids such as medications in predetermined dosages. The dispenser includes a main housing having liquid storage means, i.e. the main housing either is adapted to itself hold liquid therein or is adapted to receive and hold a component which itself will hold and store a liquid, e.g., a pouch or container. The main housing is also adapted to contain a liquid advancing means for either allowing liquid to flow out or assisting in the flow of liquid out of the main housing by exerting pressure. Thus, the liquid advancing means in the main housing is adapted to automatically advance liquid from the main housing to a metered dosage dispensing chamber in response to a loading movement of a cocking mechanism. The metered dosage dispensing chamber has an inlet connected to the main housing and has a one-way valve in the inlet to permit flow of liquid from the main housing liquid storage means to the metered dosage dispensing chamber and to prevent flow of liquid from the metered dosage dispensing chamber to said the storage means. The metered dosage dispensing chamber also has an outlet orifice for dispensing liquid therefrom in a metered amount.
The metered dosage dispensing chamber is adapted to contain a reciprocal plunger means and has a load and release means connected to it. This load and release component includes a cocking mechanism, a locking mechanism, a spring, and a plunger. The cocking mechanism is functionally connected to the plunger so as to move in harmony therewith, or, more preferably, to move a relatively short distance relative to the distance traveled by the cocking mechanism. This preferred embodiment includes the plunger and cocking mechanism connected in a slidable, non-removable manner with a predetermined, permittable distance of travel between the plunger and the cocking mechanism. The plunger is connected to and at least partially contained within the metered liquid dispensing chamber. The main spring is connected to the cocking mechanism to bias it to a first position, being a rest position toward the metered liquid dispensing chamber.
The locking mechanism is connected to the cocking mechanism to lock it in a second position, being a stressed position away from the liquid metered dispensing chamber, wherein, when the cocking mechanism is pulled away from the chamber, the locking mechanism locks the cocking mechanism in the second position, draws the plunger at least partially out of the open area of the chamber and permits flow of liquid from the liquid storage means to said chamber, and wherein, when the aforesaid locking mechanism is released, the spring biases the cocking mechanism and the plunger toward said chamber and dispenses a metered amount of liquid from the chamber.
In some preferred embodiments, the liquid advancing means is selected from the group consisting of a pressurized container, a piston-driven chamber, a collapsible pouch and a bellows-type chamber. Usually, the liquid advancing means is under a pressure insufficient to overcome said spring. In other words, the liquid advancing means does not exert sufficient force to push liquid into the chamber and to move back the plunger and cocking mechanism to cause liquid to flow into the chamber when it is not intentionally drawn into the chamber by a user pulling on the cocking mechanism.
In other preferred embodiments, the outlet orifice includes a one-way valve which is spring-loaded and permits liquid to exit the chamber and prevents air from entering chamber. In these embodiments, the liquid advancing means exerts a pressure toward the chamber which is insufficient to overcome spring and is also insufficient to overcome the spring-loaded one way valve of the outlet orifice to prevent undesirable seeping.
The present invention dispenser preferably includes a plunger stop located between the metered dosage dispensing chamber and the cocking mechanism to set a predetermined distance of travel of the plunger within the chamber.